-LRB- CNN -RRB- -- South Korea 's Red Cross has offered $ 8.4 million in flood aid to North Korea , the Yonhap news agency said Tuesday .

The aid includes medical kits , food and emergency supplies , South Korea Unification Ministry spokesman Chun Hae-sung told reporters .

The Red Cross is Seoul 's main channel for humanitarian aid to North Korea . The communist nation has not replied to the offer , Chun was quoted as saying .

The International Federation of Red Cross and Red Crescent Societies blamed a flash flood for displacing more than 23,000 people in a North Korean province bordering China .

`` The whole city of Sinuiju with its 350,000 residents is without piped drinking water at the moment because the main pumping station was inundated , '' said Henk Schipper , Red Cross water and sanitation delegate in North Korea .

In August , nearly 260,000 people in northeastern China and North Korea fled their homes as heavy rains caused the Yalu River to overflow its banks , state news outlets in those countries reported Sunday .

Tensions between North Korea and its southern neighbor have escalated since a May report from Seoul blamed North Korea for the sinking of a South Korean warship in March .

The report , whose findings have been endorsed by the United States , alleged that a North Korean sub sank the ship , the Cheonan , with a torpedo , killing 46 sailors .

North Korea denies it was responsible for the sinking .

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The Red Cross is South Korea 's channel for aid to North Korea

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The communist nation has not replied to the offer

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In August , heavy rains caused rivers to swell over